Japan Pionics Co., Ltd.

Mitsubishi Gas Chemical Company, Inc.

Masanori Iwaki

Toshio Akiyama

Kansei Izaki

Toshiaki Izumida

Yasusada Miyano

Tsuneaki Iwakiri

Chikara Sadano

The present invention provides a method of processing discharge gas containing ammonia, hydrogen, nitrogen, and an organic metal compound discharged from the production process of a gallium nitride compound semiconductor. The discharge gas is brought into contact with a cleaning agent prepared by impregnating an alkali metal compound with a metal oxide to remove the organic metal compound from the discharge gas. The discharge gas from which an organic metal compound is removed is brought into contact with an ammonia decomposition catalyst on heating to decompose the ammonia into nitrogen and hydrogen. The discharge gas in which ammonia is decomposed is brought into contact with palladium alloy membrane on heating to recover hydrogen that has penetrated through the palladium alloy membrane. After an organic metal compound is removed to liquefy the ammonia contained in the discharge gas as described above, a pressurization process and a cooling process is conducted by a heat pump to pressurize and cool the discharge gas from which an organic metal compound is removed to liquefy the ammonia contained in the discharge gas and separate the liquefied ammonia from hydrogen and nitrogen so as to recover the liquefied ammonia. The recovered hydrogen and ammonia are supplied to and reused in the production process of a gallium nitride compound semiconductor.

Method of processing discharge gas discharged from production process

There are provided methods capable of easily and efficiently recovering and recycling ammonia from exhaust gas containing a small amount of ammonia, the exhaust gas being exhausted from a production process of a gallium nitride compound semiconductor. The method of recovering ammonia includes filtering exhaust gas containing ammonia, hydrogen, nitrogen, and a solid compound with a filter to remove the solid compound from the exhaust gas; pressurizing and cooling the filtered exhaust gas with a heat pump to liquefy ammonia contained in the filtered exhaust gas; and separating liquefied ammonia from hydrogen and nitrogen to recover liquefied ammonia. The method of recycling ammonia includes evaporating recovered liquid ammonia; mixing the evaporated ammonia with another crude ammonia to obtain mixed gas; purifying the mixed gas; and supplying the purified gas to the production process of a gallium nitride compound semiconductor.

Method of recovering ammonia and method of recycling ammonia by using the same

A process for producing a resin molded article having a diminished residual stress, which includes heating an injection-molded article of a thermoplastic resin by means of a combination of far infrared radiation with far infrared ray having a frequency of from 10.sup.11 to 10.sup.14 Hz and hot-air flow, thereby to diminish a residual stress in the molded article in a short period of time.

Process for producing resin molded article having diminished residual

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Kanagawa, Japan

Masanori Iwaki